Regeneration of spent catalysts



D, 4, 1945.- E. B. PECK 2,390,323

` REGENRATION OF SPENT CATALYSTS Filed March l, 1941 3 55cm/amer fawn/v6zomc Patented Dec. 4, 1945 2,390,323 REGENERATION oF sPEN'r cA'rALYs'rsf Edward B. Peck, Elizabeth, N. J., assigner Standard Oil DevelopmentCompany, scorporation of Delaware Application March 1, 1941, Serial No.381,251

2 Claims. (Cl. 252-242) The present invention is `concerned with aprocess for the regeneration of spent catalysts utilized in variousrefining operations. The in- 'vention especially relates to a processfor the regeneration of catalysts selected fromthe class consisting ofnickel and cobalt which are utilized in -varioushydrogenatiom cracking,reforming, hydrofcrming. hydrocarbon synthesis, and related operations.

It is well known in the art. particularly in the rening of petroleumoils, to carry out hydrogeiiation, hydroforming, hydrocarbon synthesis,cracking, reforming and related operations utilizinef Various. catalyticmaterials which are usually supported on suitable base carriers, vsuchas various claystungsten. and the like. In these opelations in which acatalyst is employed. partic /arly in the treatment of petroleum oils,the catalyst after a certain time period reacts with sulfur if it is nota sulfur catalyst and also becoines coated with various carbonaceou'sand related subsfances which materially impair its'effcliency. This isparticularly the situation when the carbons, especially when elevatedtemperatures nd pressures are employed. It is therefore necessary toregenerate the catalyst and to re- `vivify the same which includes theremoval of the carbonacecusmaterials. i This is usually accnmoiished byburninq the atalyst at various temperatures and pressure conditions inorder substantially completely to free the same of` theobjectionablecarbonaceous inaterials which results in the formation ofthe sulfate.' While this operation is entirelyrsatisactory for thetreatment of certain materiels, as for example, for the treatment ofiron oxide, Viron sulde, and the like, which substances are employed ascatalysts in various operations. it is not particularly suitable for theregener'ftion of catalysts such as nickel oxide, nickel suliide. cobaltoxide and cobalt sulde..

For example. if the fresh catalyst comprises l ferric oxide. whichcatalyst upon continuous use inthe presence of asulfur-containingoildeteriorates to 4ferrous sulfide, the same may be readily regeneratedby'o'xidizing in the presence of steam.- Under these conditions, theferrous.

feed materials comprise petroleum hydro` I readily utilized in theregeneration spent cata- -substantially above A600 lyst comprisingcobaltand .nickehsch as. cobalt- 1 oxide, cobalt sulfide, nickel xldef"iand vnickel sulfide. This is due to the fact .that a "spent catalystsuch as nickel suldebe heated limmediately to 600-C. the 'reaction-Willnot vgo tocompletion with respect to nickel'sulfate. Furthermore, it isnot practical C. due tofthe factthat it may adversely alect` the base4carrier andi-cause further deleterious results.` It has therefore beenthe practice to use non-reducibleloxides, such as zirconium oxide,aluminum silicaoxide.; and the like, in many operations even though thenickel and cobalt oxides and suldes in many-iifistianzes are superior.This was due to the fact thatthe former type of catalyst could bereadily `revivirled With a small amount o f catalyst loss whereas. thiswas not the situation with respect to the latter type of catalyst.

' I have, however, now discovered a pr cessby which catalystsfof thetype of nickel oxide and the like may be readily regenerated whibroomprises utilizing a particular sequencei;v In an initial stage thecoke or tar isb the catalyst is subjected in a secondary oxidizingatmosphere, preferably'in th of a large amount vof steam and at atemperature for a time period necessi the desired constituents. Theparta-i i 1 p ated catalyst is then subjected ina terti ry'sta-'ge totreatment adapted to regenerate completely the same. My invention maybel readilyjiinderstood by reference to the diagrammatical illustratingone embodiment of the same.

For the purpose of description it is assumed that the catalyst comprisesnickel oxide sind that the same is utilized in the alkylation ofia sule'fur-containing petroleum oil. 'I'heipetroleum oil is introduced intocontacting zone I'by ineens of feed line 2 wherein itis treated `with acatalyst comprising nickel oxide supported on a tungsten carrier.Temperature and pressure condi` sulfide reacts to form ferricsulfate'which latter substance further reacts to form the ferric oxideand sulfur tri-oxide. In an operation of this character, the ferricoxideis substantially completely regenerated in an elcient manner and ata relatively low temperature of about 600"V C.

On the other hand, this operation cannot be tions are adjusted in zone lto secure the desired yalkylation of the oil. The treated oil isWithdrawn from zone -I by means of line 3 and further handled asdesired. After the activity of the catalyst has decreased in zone i to apredetermined etliciency the feed oil is passed through zone icontaining a similar catalyst by means of line 5, withdrawn by means ofline 6 and handled as desired. The method used with respect to.regenerating the catalyst in zone 4 `is entirely similar with respectto the method of regenerating the catalyst removed from zone I.

to raise vthe temperature ceous materials and nickel sulfide, iswithdrawn lfrom zone I by means of line 1 and `subjected to an initialoxidation-treatment in zone 8. In this zone temperature and pressureconditions are initially adjusted `to remove the carbonaceousconstituents from the catalyst whereby a portion of the nickel isconverted to the sulfate. After the carbonaceous constituents areremoved, the treatment is continued at particular temperature conditionswhich are adapted and regulated so that the ratio of nickel suldedissolved in nickel sulfate is approximatelyv 1 to'3. The catalystcomprising' a solid solution of nickel sulfide dissolved in nickelsulfate which contains about 25 mol percent nickel sulfide and 75 molpercent `nickel sulfate is withdrawn from zone 8 by means of line 9 andpassed into secondary heating .zone I0 wherein the temperature of thesame ls raised and controlled whereby a reaction between the nickelsulfide and the nickel sulfate occurs, resulting in the formation ofnickel oxide and sulfur dioxide. The sulfur dioxide is removed by'meansof line Il while the nickel oxide is removed by means of line I2 andrecycled to. treating zone I.

The process of the present invention may be` widely varied. Theinvention essentially comprisesv regenerating spent nickel oxide, nickelsulde, `cobalt; oxide, and cobalt sulde by subjecting the same to 'twodistinct heat treatments. In the initial heat treatment the temperatureand-pressure conditions are regulated to remove the objectionablecarbonaceous constituents and so as to form a predetermined proportionof the sulde to the sulfate. In this zone the pressure employedispreferably atmospheric pressure and the temperature is in the generalrange from about 475 C. to-575" C., preferably in the range from about500 C. to 550 C. Conditions in general are so regulated to produce asolution of nickel sulfide dissolved in nickel sulfate in which ltheproportion 'is approximately `20 to 30 mol percent nickel sulde to 70-to 80 mol percent nickel sulfate. Every eifort is made to securela I25mol percent nickel sulfide dissolved in '15%` nickel sulfate. Y

In the secondaryheating stage. the solution of nickel sulfide -andnickel sulfate is held at a temperature adapted to produce a reactionbetween the sulde and sulfate resulting in the formation of nickel oxideand sulfur dioxide.

This issecured by regulating the temperature in` the general rangefromabout 590 C. to 650 C.,

'preferably in the range'from about 600 C. to-

Under certain conditions it may be desirable to.utilize relatively purenickel or pure cobalt in the treating zone. If this type of operationbey employed, thel cobalt removed from zone I0 by 'means of line I2' ispassed to zone I3 wherein the same Y is hydrogenated at a temperature inthe general range from about 350 C. to form the pure .The spent nickelcatalyst comprising carbonametal which isremoved by means of line I land passed to zone I. If it isl preferred that the catalyst comprise thesulfide of the cobalt or nickel, this may readily be secured by passingthe cobalt or nickel removed from zone I3 to zone I5 wherein the sulfideof the metal is formed by known means.. The sulfide may then be passedto zone I or zone 4 as desired.

In order to illustrate my invention further, ,the following example isgiven which should not be construed as limiting the same in any mannerwhatsoever.

' Example In various operations it was found that if the nickel 'sulfidewere heated ata temperatureof about 600 C., it was not possible to'fully reactivate the catalyst.

In another operation it `was found that if the nickel sulfide wereheated to a temperature ofA about 525 C. and held at that temperature.and thenrraised to 600 C., the nickel 'was entirely converted to oxide.

Although I do not wish" to be restricted, it ,is my belief thatv themechanism of the operation is as follows:

When the nickel sulfide is heatedat a temperatre of about 500 C., aportion of thenickel vsulfide is .converted to the nickel sulfate. Thisportion comprises approximately mol percent as compared to theunconverted nickelV sulfide. After equilibrium is reached with respectto the nickel sulde and nickel sulfate by raising the solid solution ofnickel sulfide and nickel sulfate to `600 C., the following reactionoccurs:

thereafter raising the temperature of the solid j solution toabout 600".C. to cause the sulfate to oxidize the sulde to oxide. I

2. v'I'he process for th'e regeneration of nickel catalystv on atungsten carrier which catalyst hasv been converted to nickel sulde intherening of petroleum oil, which comprises heating the nickel sulfideat about 500 C. in the presence of steam thereby oxidizing said s uldet0 a solid solution formed of 75% nickel sulfateand 25% nickel sulnde,and thereafter raising the temperature of th'e solid solution to about600 C. to cause the nickei sulfate to oxidize the nickel s ulnde tonickel oxide.

- EDWARD PECK.

